Method and arrangement for selectively controlling fluid discharge from a drill bit on the lower end of a drill string



Jan. 6, 1970 E. A. ANDERSON METHOD AND ARRANGEMENT FOR SELECTIVELY CONTROLLING FLUID DISCHARGE FROM A DRILL BIT ON THE LOWER END OF A DRILL STRING S SheetsSheet 1 Filed Dec. 21, 1967 EDWIN A. ANDERQON INVENTOR.

Mania 6 Maflxeum ATTORNEYS Jan. 5, 19m

E. A. ANDERSON 3,4$,76 METHOD AND ARR GEMENT F0 SELECTIVELY CONTROLLING FLUID DISCHA FROM A LL BIT ON THE LOWER END OF A DRILL STRING 3 Sheets-5lzeet 2 Filed Dec, 21, 1967 VENTOR.

EDWIN A AWE .lllv

madm- PMMJ Ma ww ATTORNEYS Jan. 6, 1970 E. A. ANDERSON 488.765

METHOD AND ARRANGEMENT FOR SELEUTIVELY CONTROLLING FLUID DISCHARGE FROM A DRILL BIT ON THE LOWER END OF 'A DRILL STRING Filed Dec. 21, 1967 3 Sheets-Sheet 3 a! A I me,

j -76 7a 78a 64" :2 I 39 ,54? g; $29 Q1 u W l 24' w s: l\\ \l9a k sowm A. ANDERSON INVENTOR. 22 2g F E.GA BY Magda. 6 MaHLewL ATTORNE' Y5 United States Patent 3,488,765 METHOD AND ARRANGEMENT FOR SELEC- TIVELY CONTROLLING FLUID DISCHARGE FROM A DRILL BIT ON THE LOWER END OF A DRILL STRING Edwin A. Anderson, 1104 Chimney Rock, Houston, Tex. 77027 Filed Dec. 21, 1967, Ser. No. 692,532 Int. Cl. E21b 7/04, 9/02, 9/34 U.S. Cl. 17561 13 Claims ABSTRACT OF THE DISCLOSURE An arrangement to be connected in a drill string to selectively control fluid discharge from a drill bit on the lower end of the drill string so that the drilling fluid may be discharged through all of the nozzles of a drill bit or through only one of the nozzles of the drill bit, and a method for selectively discharging the hydraulic horsepower and drilling fluid through the nozzles of a drill bit.

CROSS REFERENCE TO RELATED APPLICATION The present invention is directed to an arrangement for use with a directional hit, one form of which is illustrated in my United States Letters Patent No. 3,360,057 issued on Dec. 2.6, 1967.

BACKGROUND OF THE INVENTION Field of the invention The present invention is directed to an arrangement and method to drill deviated bore holes such as oil, gas, or water wells and the like. More particularly, it relates to the method and arrangement for drilling deviated holes by the jetting action of drilling fluid discharged from the drill bit on the lower end of a drill string and selectively direct all of the drilling fluid through only one nozzle in the drill bit or to discharge the drilling fluid through all of the nozzles in the drill bit without removing the drill pipe from the well bore.

Description of the prior art United States Letters Patent No. 2,873,092 discloses a form of bit which includes a boot therein to direct drilling fluid or discharge the drilling fluid from the drill string through only one nozzle in the drilling bit. This is disadvantageous in that it may be desired to deflect or deviate only a certain portion of the well bore and when the desired deviation has been accomplished it is then desirable to discharge the drilling fluid through all of the nozzles in the drilling bit. However, with the construction of the above mentioned patent, it can be appreciated that once the rubber boot has been removed from the bit, it cannot thereafter be reinserted in the bit without removing the entire drill string from the well bore. This procedure is time consuming and expensive.

Another common procedure is to blank off the jet nozzles in the drill bit except one which is larger and through which all of the drilling liquid is discharged. However, there are certain disadvantages in blanking the two small jet nozzles when normal drilling is resumed. For example, the penetration rate of the drill bit may be reduced because of the limited washing action available to clean the cones of the drill bit in the bottom of the hole.

Also, since all of the jet nozzles are closed off except the large one, the bit may ball-up more easily since the other nozzles are blanked off. A bailed-up bit may not respond to variations of weight and rotary speed as effectively as a cleaner bit, and this affects drilling control.

Furthermore, should the drilling become too sticky and if the bit should ball-up, it may be necessary to remove the pipe from the well bore and install the small jet nozzles.

Another prior art form of deviating the well bore is to use, for example, a tricone rotary drilling bit with one large nozzle, such as, for example, one having a inch to inch discharge opening, and using two smaller nozzles such as, for example, each having a A inch to A inch discharge opening. There may be some disadvantages with this type of arrangement in that a greater length of time may be required to make 'a jet deflection run in the well bore since all of the mud flow is not localized in the desired direction.

Also, the two smaller nozzles may be detrimental to the, jet deflection operation because the extra volume of mud that is required to feed the small nozzles may cause a higher friction loss in the drill pipe, and thus reduce the effective hydraulic horsepower across the bit. This in turn may reduce the hydraulic horsepower for the large jet nozzle.

Additionally, the mud pressure drop and velocity through the small nozzles are the same as that through the large nozzle; however, the volume through the smaller nozzles as compared with the volume through the large nozzle is not the same. Also, the flow of drilling fluid through the small nozzles may erode the natural shoulder or formation which serves as a whipstock to guide the bit entering the deviated portion of the well bore. There have been some cases in which the well bore has actually been deflected in the direction of the small jet nozzles instead of in the direction of the large nozzles, which is undesirable.

Another disadvantage may be that jet deflection cannot be accomplished at as great a depth because of the decreased hydraulic horsepower across the bit and the possible eroding action of the small jet nozzles in the opposite direction. This may necessitate resorting to more time consuming and expensive methods such as utilizing a whipstock or fluid motor drills, which may be more time consuming and expensive.

SUMMARY OF THE INVENTION The present invention overcomes some, if not all, of the above objections encountered in jet deflection or jet deviation in that it provides an arrangement and a method so that the drilling fluid may be selectively discharged through all of the nozzles of the drilling bit during normal drilling operations, or the drilling fluid may be discharged only through one of the nozzles when it is desired to deviate the well bore.

Additionally, the present invention is constructed and arranged so that it may be easily actuated without removing the drill string and the drilling bit from the well bore. Also, it may be actuated as many times as desirable without necessarily removing the drill string from the well bore.

The use of what is termed a float valve in many areas is standard practice so as to prevent backflow in the drill string when a survey instrument is run and to eliminate lost time in equalizing the mud column. It may also be used to provide a shut-off or check valve against either high or. low pressures from fluid or gas beneath the float valve which otherwise would flow into the drill string.

Another advantage of the present invention is that it is constructed and arranged so that it does not interfere with the normal use of a float valve in drilling operations.

Generally speaking, the primary object of the present invention is to provide an arrangement and method whereby the drilling fluid which is conducted through the drill string and discharged through the drill bit at the lower end thereof in drilling operations may be selectively discharged through only one of the nozzles of the bit to accomplish jet deflection when desired, or to discharge the fluid through all of the nozzles when desired without removing the well pipe and drill bit from the well bore while also providing the safety and convenience of a float valve. Such procedure can be repeated as many times as desired while drilling a well bore without removing the pipe and drill string from the well bore to accomplish the desired results as is required with some prior art arrangements.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a sectional view illustrating the upper part of one form of the present invention and shows the relationship of the various components when drilling liquid is being discharged through all of the nozzles in the bit, except the float valve is shown closed and it would be open when drilling fluid passes from the drill string to the bit;

FIG. 1A is a sectional view on the line 1A-1A of FIG. and is a continuation of FIG. 1 and shows in greater detail the interior of a partitioned drill bit. The cutting cones of the bit have been omitted for clarity;

FIG. 2 is a sectional view of the upper part of the tool shown in FIG. 1 and illustrates the relationship of certain components when the device has been actuated so that all of the jet nozzles in the drilling bit are closed except one; again the float valve is shown closed, but would be open as stated with regard to FIG. 1;

FIG. 3 is a sectional view and a continuation of FIG.

FIG. 3A is a sectional view similar to FIG. 1A and shows valve means seated on a partition means in the drilling bit so that all of the liquid is discharged through only one nozzle to accomplish desired deflection of the bore hole;

FIG. 4 is a sectional view on the line 44 of FIG. 2 to show one arrangement for supporting the upper portion of the device in a drill string;

FIG. 5 is a view on the line 55 of FIG.1A;

FIG. 6 is a sectional view of the upper part of another embodiment of the invention;

FIG. 6A is a sectional view similar to FIG. 1A and shows the device when it has been actuated so that all of the drilling liquid from the drill string is discharged through only one jet nozzle in the drilling bit, except the float valve would be unseated to accommodate fluid passage to the bit;

FIG. 7 is a sectional view of the uppermost end of the tool shown in FIG. 6;

FIG. 8 is an enlarged detail of the portion circled in FIG. 1;

FIG. 9 is a side view of a form of partition means for a drill bit; and

FIG. 10 is another view of the partition for use in a drill bit.

DESCRIPTION OF THE PREFERRED EMBODIMENT Attention is first directed to FIG. 1 of the drawings wherein a portion of a drill bit is illustrated at which is connected by suitable means such as the threads 16 to the lower end of a drill string represented in dotted line generally at 18.

The drill bit 15 is provided with a partition means 19 within the bore 20 of the drill bit 15. The construction of the bit 15 and the arrangement of the partition means 19 therein may be as disclosed and claimed in my United States Letters Patent No. 3,360,057, issued on Dec. 26, 1967.

Since a portion of the bit 15 has been cut away, the partition means 19 is shown as covering only one jet nozzle; however, as disclosed in the above referred to patent, such partition means communicates with the two smaller jet nozzles in a three nozzle drilling bit so that the drilling fluid may be separated in the bore 20 and selectively directed to the larger bore jet nozzle represented at 22 when the invention assumes the relationship shown in FIG. 3 of the drawings or the fluid from the bore 20 will be conducted to all of the jet nozzles in the bit 15 when the relationship of the components is as shown in FIG. 1 of the drawings. FIG. 9 shows one form of a partition, and FIG. 5 shows the bottom of the partition 19 as well as jet deflection nozzle 22 and drilling or smaller discharge nozzles 22.

The partition means 19 may be of any suitable form and is preferably provided at its upper end 23 with a seat 24 for receiving valve means 25 as will be described in greater detail. Seated on the upper end 28 of the bit 15 is a housing 29 provided with a downwardly facing seat as illustrated at 30. The housing 29 is also provided with a web support means 31 with the opening 32 therein. The opening 32 is provided with the member 33 which surrounds the bushing 35. A spring 36 is seated on the bushing 35 and abuts the bottom 38 of the check valve 39 to normally urge it against the downwarly facing seat 30. The check valve 39 may be provided with a suitable resilient material 40 to aid in sealing off when the check valve 39 is seated on seat 30. The valve 39 is normally termed in the art a float valve and in some areas it is standard to use a float valve. It permits fluid to pass downwardly from the drill string bore 41 and therearound to be discharged out the nozzles of the drilling bit 15, but prevents passage of fluid from beneath the valve 39 back into the bore 41 of the drill string 18. Suitable seal means as illustrated at 43 are provided between the housing 29 and the drill string 18 or sub in which the housing 29 is seated to inhibit leakage of fluid thereby.

A valve rod 47 is illustrated in FIG. 1 having the valve means 25 mounted on the lower end thereof by any suitable means such as the threads 47. If desired, a suitable resilient material 48 may be provided to aid in sealing ofl with the seat 24 when the valve means 25 is abutted against the partition means 19 as shown in FIG. 3.

The valve rod 47 extends longitudinally of the drill string and is normally urged towards abutting relationship with the seat 24 on partition means 19 by reason of the spring 50 which rests on the shoulder 51 of the valve means 25 and abuts the bushing 52 which is seated on the bottom 53 of the web support 31. Movement of the valve rod 47 longitudinally to seat the valve means on the partition means 19 is inhibited by reason of the restraining means referred to generally by the numeral 60 in the upper part of FIG. 1. It will be noted that the upper end 61 of the rod 47 is threadedly engaged as shown at 62 with the member 63, thereby providing an annular shoulder 64 for a purpose to be described.

The upper part of the valve rod 47 is telescopically received within the hollow sleeve 65 as shown in FIG. 1 of the drawings. The hollow sleeve 65 is in turn supported in any suitable manner in the drill string, and as illustrated is shown as being supported on the web member 66 which is seated within the grooves 67 formed in the upper end of the housing 29.

As illustrated in FIG. 8, the lower end of sleeve 65 is provided with an annular groove 65a spaced from the lower end 65b of the hollow sleeve. The web member 66 includes the three legs 66a and the central hub 66b through which a bore 660 extends. The bore 660 is counterbored as shown in FIG. 8 at 66d, such counterbore extending up to the end of the annular groove 65a in the hollow sleeve 65 and terminating in an arcuate manner as represented as 66e which termination conforms with the curvature of the groove 65a. An annular ring 70 may be positioned in the groove 65a, and the hollow sleeve 65 then positioned within the bore 660 of the hub 66b. Any other suitable arrangement could be provided to mount sleeve 65 slidably relative to web member 66.

A spring 72 rests on the top of the hub 66b and abuts the shoulder 73 formed on the hollow sleeve 65 and functions as a shock absorber when the device is actuated as will be described hereinafter.

The hollow sleeve 65 may be provided with any suitable number of circumferentially spaced windows or slots 74 in which are pivotally mounted the members 75 by means of the pin 76 extending through each of the members 75 and into the adjacent wall of the slots or windows 74 of the hollow sleeve 65.

It will also be noted that the pivotally mounted members 75 have a cutout portion to accommodate the spring 78 which fits around the pivot pin 76, such spring means normally tending to urge the pivotally mounted members 75 radially outward relative to the hollow sleeve 65 and the valve rod 47. The upper end 80 of each of the pivotally mounted members 75 is thereby engaged with the shoulder 64 and thus restrains longitudinal movement of the valve rod 47. When in this position, the drilling fluid will pass through the bore 41 in the drilling fluid will pass through the bore 41 in the drilling string around the web 66 and around check valve '39 and around the web 31 into the bore 20 of the bit 15 and will be discharged through all of the nozzles in the drilling bit, both the large deflection jet nozzle and the two smaller drilling nozzles.

When it is desired to actuate the device, the hollow member 81 with a fishing neck 82 on the upper end thereof is dropped in the well string and moves to the position shown in FIG. 2 of the drawing so as to telescope over the hollow sleeve 65.

When this occurs, the pivotally mounted members 75 are moved inwardly within the windows 74 as shown in FIG. 2 of the drawings whereupon the end 80 of each of the members 75 disengages from the shoulder 64 and the spring 50 urges the valve means 25 into engagement with the partition means 19 so that drilling fluid from the bore 41 of the drill string flows around member 81 to the bit bore 20 and is thereafter conducted only to the large deflecting nozzle represented at 22, and prevented from flowing to nozzles 22'. As previously noted, the partition means 19 is arranged as disclosed in United States Letters Patent No. 3,3 60,057 so as to communicate with the smaller drilling jet nozzles, one of which is not illustrated in the drawings.

From the foregoing description, it can be seen that all of the drilling liquid from the drill string is communicated through the bore 20 of the bit 15 and discharged only through the deflecting nozzle 22 for the jet deflection operation.

Following the jet deflection operation, it is customary to drill one or more joints before a directional survey is run, and of course during this period member 81 is in place and all of the drilling fluid flows through the large jet nozzle only.

Also, it should be further understood that a nonmagnetic drill collar equipped with orienting magnets is utilized in order that a survey may be taken in a manner well known in the art. A scribe line is aflixed on the collar in alignment with the north magnets so as to. predetermine the position of the large jet nozzle with respect to the north magnets before the bit is lowered into the well bore. This is done in a manner well known in the art.

It should be further understood that the combined length of member 81, the wireline overshot, and the survey instrument assembly must be prespaced with suitable lengths of instrument sinker bars so when member 81 is resting on the top of 66b, the orienting compass in the survey instrument will be directly opposite the orienting magnets in the nonmagnetic drill collar.

After one or more joints have been drilled following the jet deflecting operation, the survey instrument is run along with the wireline overshot on the lower end thereof. The wireline overshot will latch on the fishing neck 82 of member 81, and the survey picture is taken. When the survey instrument is removed, member 81 is also removed from the well bore. If the survey indicates that the well bore is not proceeding in the desired direction, then hollow member 81 is dropped back in the drill string and pumped down and further jet deflection continued. If, however, the survey indicates that the well bore is proceeding in the desired direction, then of course further deviation will not be desired.

After the survey instrument and the hollow member have been retrieved to the surface, the slips are taken out of the rotary table in a manner well known in the art and the drill string is then lowered several feet before starting the pumps. The hydrostatic pressure below the float valve acting on the cross-sectional area of the valve stem will force the valve stem 47 up into the hollow sleeve 65 and when it is forced up in this manner the pivotally mounted members 75 re-engage the shoulder 64 to hold the valve rod 47 in the position shown in FIG. 1 of the drawing. The reengagement of members 75 with shoulder 64 may occur without lowering the drill string and merely by removing member 81 when the hydrostatic head below float valve 39 is greater than it is inside the drill string.

Thereafter, normal drilling operations may continue.

If further jet deviation or drilling is desired, the hollow member 81 is again dropped to release the valve rod and close off the drilling jet nozzles and conduct all of the fluid to the large deflecting nozzle to accomplish the desired deflecting operation. For example, the large jet deflecting nozzle may have a discharge opening /3 inch in diameter, and the two jet drilling nozzles may have a discharge opening A inch in diameter. The nozzles may be held in the bit in any one of several ways, such as with an O-ring seal and snap ring as shown. In some instances, the deflecting jet may be brazed or welded in place, or it may be held in place with epoxy resin.

Referring now to FIGS. 6, 6A, and 7, the device in the form there illustrated is shown in its actuated position as the hollow member represented by the numeral 81' when the fishing neck 82' thereon has been lowered into the well bore. The drilling bit is again illustrated and represented by the numeral 15' and is provided with partition means 19' to accomplish the same function and purpose as that described with regard to FIGS. 1 through 4. The housing 29 is similar to the housing 29 and the check valve 39' is similar to the check valve 39 described in FIG. 1.

A slightly different form of seat 24' is shown and a slightly different form of valve means 25' is also shown on the valve rod 47' which is similar to the valve rod 47 previously described.

In the form shown in FIGS. 6, 6A, and 7, the hollow sleeve 65' is integral with the web member 66' and the members 75 which are pivoted on the pin 76' within the slots 74 formed in the hollow sleeve 65. It will be noted that in the form of the invention shown in FIG. 6, the pivotally mounted members 75 are urged outwardly by reason of the spring means 78' which fits around the hollow sleeve 65' and is engaged within a groove 78a formed in each of the pivotally mounted members 75'. The spring 78' urges the pivotally mounted members 75' outwardly relative to the hollow sleeve '65 as described with regard to the form of the invention shown in FIGS. 1 and 1A, and the ring which is slidable on valve rod 47' has shoulder 64' on its lower end with which the ends 80' of each of the pivotally mounted members 75' engage when the valve rod 47' is in up position.

Spring which surrounds the upper end of the valve rod 47' acts as a shock absorber for the pivotally mounted members 75' when the valve rod 47 is in its uppermost position.

In FIGS. 9 and 10, the partition means 19 is shown in greater detail, and when welded in the bit 15, the bore 19a communicates fluid from the drill bit bore 20 to discharge nozzles 22 when valve member 25 is not on seat 24, and when valve member 25 is on seat 24, fiuid flow to discharge nozzles 22' is prevented and all fluid dis- 7 charges through the larger discharge opening in nozzle 22.

The foregoing disclosure and description of the invention are illustrative and explanatory thereof, and various changes in the size, shape and materials as well as in the details of the illustrated construction may be made within the scope of the appended claims without departing from the spirit of the invention.

I claim:

1. An arrangement to be connected in a drill string for selectively controlling fluid discharge from a drill bit on the lower end of the drill string to effect jet bit deflection comprising:

(a) a drill bit with a bore for receiving fluid from the drill string;

(b) nozzles mounted in said bit to discharge the fluid from the bit;

() partition means in said bit for separating fluid flow in the bit bore and selectively directing it to said nozzles;

((1) means operatively associated with said bit to abut the upper end of said partition means and close ofl fluid discharge through all of said nozzles except one, said means including:

(1) a housing carried within the drill string with a downwardly facing valve seat thereon;

(2) check valve means mounted in said housing to accommodate flow from the drill string to the bit bore, but preventing fluid flow from beneath the valve into the drill string;

(3) a valve rod movable longitudinally of said housing and through said check valve;

(4) valve means on the lower end of said rod for abutting said partition means and thereby close off fluid discharge through all of said nozzles except one;

(5) spring means normally urging said valve means to abutting relationship with said partition means;

(6) a hollow sleeve telescopically receiving the upper end of said valve rod;

(7) means pivotally mounted in said sleeve and engaging sad valve rod above said check valve to hold said valve rod against longitudinal movement within said housing and thereby inhibit engagement of said valve means and partition;

(8) spring means abutting said pivotally mounted means to normally urge said pivotally mounted means in holding relationship with said valve rod to thereby prevent longitudinal movement of said valve rod; and

(9) said pivotally mounted means projecting radially outward relative to said sleeve and being adapted to pivot inwardly by the insertion of a hollow member in the drill string.

2. The invention of claim 1 including seal means between said housing and drill string.

3. The invention of claim 1 including seal means between said valve rod and check valve means.

4. The invention of claim 1 wherein said partition means includes a seat on its upper end for receiving said valve means on the lower end of said rod.

5. The invention of claim 1 including shoulder means on said valve rod for abutting with said pivotally mounted means to hold said valve rod against longitudinal movement.

6. The invention of claim 1 including a spring support means in said housing and a spring carried thereon and abutting said check valve means to normally urge it to closed position.

7. The invention of claim 1 including support means carried by said housing to support said hollow sleeve.

8. The invention of claim 7 including latch means to latch said support and sleeve together.

9. The invention of claim 7 including a shoulder on said sleeve and spring means abutting said support and said should to accommodate any shock on said sleeve where said hollow member telescopes thereover.

10. An arrangement to be connected in a drill string for selectively controlling fluid discharge from a drill bit on the lower end of the drill string to elfect jet bit deflection comprising:

(a) a drill bit with a bore for receiving fluid from the drill string,

(b) nozzles mounted in said bit to discharge the fluid from the bit;

(0) partition means in said bit for separating fluid flow in the bit bore and selectively directing it to said nozzles;

((1) means operatively associated with said bit to abut the upper end of said partition means and close off fluid discharge through all of said nozzles except one, said means including:

(1) a valve rod supported in the drill string for longitudinal movement;

(2) valve means on the lower end of said rod for abutting said partition means and thereby close ofi fluid discharged through all of said nozzles except one;

(3) spring means normally urging said valve means to abutting relationship with said partition means;

(4) means for restraining said valve rod against longitudinal movement; and

(5) means operatively associated with said restraining means to release said restraining means from said rod whereupon it moves longitudinally to abut said valve means against said partition.

11, The method of selectively discharging from the drill string all the hydraulic horsepower in drilling fluid through only one nozzle of a drill bit during jet bit deflection and through all nozzles of a drill bit when not jet bit deflecting, without removing the drill string from a well bore, comprising the steps of:

(a) partitioning the bore of a drill bit having discharge nozzles thereon for separating fluid flow in the bit more to selectively direct it to the discharge nozzles;

(b) inserting a spring loaded valve means in the drill (0) connecting the partitioned drill bit to the lower end of a drill string beneath the spring loaded valve means;

((1) restraining the valve means in spaced relation to the partition in the bit whereby the hydraulic h rsepower in the drilling fluid is discharged through all of the nozzles; and

(e) releasing the restraining means so that the valve means engages the partition and closes off all nozzles except one whereby all the hydraulic horsepower is discharged therethrough.

12. The method of selectively discharging from the drill string all the hydraulic horsepower in drilling fluid through only one nozzle of a drill bit during jet bit deflection and through all nozzles of a drill bit when not jet bit deflecting, without removing the drill string from a well bore, comprising the steps of:

(a) partitioning the bore of a drill bit having discharge nozzles thereon for separating fluid flow in the bit bore to selectively direct it to the discharge nozzles;

(b) inserting a spring loaded valve means in the drill string;

(0) connecting the partitioned drill bit to the lower end of a drill string beneath the spring loaded valve means;

(d) restraining the valve means in spaced relation to the partition in the bit whereby the hydraulic horse- 9 power in the drilling fluid is discharged through all of the nozzles;

(e) releasing the restraining means so that the valve means engages the partition and closes off all nozzles except one whereby all the hydraulic horsepower is discharged therethrough; and

(f) recovering the releasing means from the well bore whereupon the drilling fluid may be discharged through all the nozzles.

13. The method of selectively discharging from the drill string all the hydraulic horsepower in drilling fluid through only one nozzle of a drill bit during jet bit deflection and through all nozzles of a drill bit when not jet bit deflecting, without removing the drill string from a well bore, comprising the steps of:

(a) partitioning the bore of a drill bit having discharge nozzles thereon for separating fluid flow in the bit bore to selectively direct it to the discharge nozzles;

(b) inserting a spring loaded valve means in the drill string;

(c) connecting the partitioned drill bit to the lower end of a drill string beneath the spring loaded valve means;

(d) restraining the valve means in spaced relation to the partition in the bit whereby the hydraulic horsepower in the drilling fluid is discharged through all of the nozzles; (e) releasing the restraining means so that the valve means engages the partition and closes ofl all nozzles except one whereby all the hydraulic horsepower is discharged therethrough;

(f) recovering the releasing means from the well bore;

and

(g) lowering the drill string to recock the restraining means and open the valve means whereupon the drilling fluid may be discharged through all the nozzles.

References Cited UNITED STATES PATENTS 25 NILE C. BYERS, JR., Primary Examiner 

